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Res Locals

_includes/api/en/5x/res-locals.md

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<h3 id='res.locals'>res.locals</h3>

Use this property to set variables accessible in templates rendered with res.render. The variables set on res.locals are available within a single request-response cycle, and will not be shared between requests.

<div class="doc-box doc-warn" markdown="1"> The `locals` object is used by view engines to render a response. The object keys may be particularly sensitive and should not contain user-controlled input, as it may affect the operation of the view engine or provide a path to cross-site scripting. Consult the documentation for the used view engine for additional considerations. </div>

In order to keep local variables for use in template rendering between requests, use app.locals instead.

This property is useful for exposing request-level information such as the request path name, authenticated user, user settings, and so on to templates rendered within the application.

js
app.use((req, res, next) => {
  // Make `user` and `authenticated` available in templates
  res.locals.user = req.user
  res.locals.authenticated = !req.user.anonymous
  next()
})